1. Field of the Invention
This invention generally relates to rigid take-out inserts for metallic take-out tong members which are adapted to handling hot glass articles such as containers immediately following their blow molding. The inserts are comprised of composite materials which are durable and heat resistant, and capable of handling the hot glass articles without damaging their contacted surfaces. The inserts are primarily formed of moldable thermosetting, heat-cured plastic material with a metallic insert having at least two exposed working surfaces with its main body portion disposed within the plastic material to control its working temperature. The metallic working surfaces are capable of being thermally controlled during their continuing long term use by surrounding insulating plastic material . The exposed working surfaces of metal are preferably employed to both grasp the hot glass articles and provide non-wearing support of the insert within a metal tong member. The insert is provided with apertures for floating self-centering support of the insert when utilized in pairs within juxtaposed tong members, or alternately, may be rigidly mounted.
The plastic material may consist of a wide variety of primarily organic moldable thermosetting materials adapted to high-temperature resistance and non-checking of the hot glass. The preferred material is comprised of organic silicone resin with particulate fillers such as graphite and chopped glass fibers therein, although other plastics such as polyimides may also be used. The inserts are molded with the reinforcing metallic member such as carbon steel mounted therein in generally co-planar relation depending upon end use.
The inserts preferably have three exposed metallic working surfaces, i.e. a semi-circular shape for grasping the hot glass articles such as containers, a diametrically-disposed flanged surface for non-wearing back support of the insert, and at least a pair of apertures for retention of the insert in a metal tong member such as by a suitable pair of spring detents.
2. Description of the Prior Art
It has been common practice in the manufacture of glass articles such as containers by blow molding to use a wide variety of high-temperature materials to cover the working surfaces of mold take-out tongs. As is well known, take-out tongs require high-temperature resistant materials on their glass contacting surfaces, and more specifically, materials which do not damage the hot glass. The most commonly used takeout tongs are all metal such as stainless steel, brass and the like. These can perform the takeout operation satisfactorily when they operate at a temperature high enough so that they do not cause thermal defects in the contacted glass surfaces. If the metal is too cold, thermal defects in the glass can occur. This invention involves the use of thin metal surfaces which will heat rapidly, and which are also entirely or partially insulated to slow or retard metal cooling. Consequently, the metal is maintained at a temperature high enough so that thermal glass damage does not occur.
U.S. Pat. No. 4,382,998 to Stengle and Minneman relates to a heat-resistant molding composition and molded parts for handling hot glass articles. The molding composition comprises a cured, thermoset, organopolysiloxane resin containing a fibrous filler of heat-resistant glass fiber material and a powdered graphite filler. Such thermosetting composite materials are adapted to be molded into heat-resistant parts such as take-out inserts. However, in the teaching of this patent all metal reinforcing members are embedded within the composite plastic material beneath their glass contacting surfaces. The only exposed metal is in the retention area for supporting the parts such as at hollow post-like edges. While the plastic composite material is useful in practicing the present invention, the disclosure relates to vastly different structures such as universal molded-to-shape conveyor hardware items for transporting hot glass articles. The disclosed tong inserts are molded to shape from the composite plastic material alone, or with reinforcing metal members full embedded. The referenced patent is owned by the same common assignee as the present application.
Also U.S. Pat. Nos. 4,246,313 and 4,110,095 both issued to Stengle relate to heat-resistant composite materials and coating glass forming molds with solid film lubricant layers respectively, both of these patents being owned by the same common assignee as the present application.